Bittersweet Chocolate Roulade

A roulade gets its name from the French word, literally meaning “to roll.” This delicious take on the traditional yule log uses bittersweet chocolate with espresso mascarpone cream to give a sophisticated new taste to that holiday classic.

SERVES 8 TO 10

We suggest that you make the filling and ganache first, then make the cake while the ganache is setting up. Or, if you prefer, the cake can be baked, filled, and rolled—but not iced—then wrapped in plastic and refrigerated for up to 24 hours. The roulade is best served at room temperature.

2. Bring 2 inches water to simmer in small saucepan over medium heat. Combine chocolate, butter, and water in small heatproof bowl and cover tightly with plastic wrap. Set bowl over pan, reduce heat to medium-low, and heat until -butter is almost completely melted and chocolate pieces are glossy, have lost definition, and are fully melted around the edges, about 15 minutes. (Do not stir or let water boil under chocolate.) Remove bowl from pan, unwrap, and stir until smooth and glossy. While chocolate is melting, sift 1/4 cup cocoa, flour, and salt together into small bowl and set aside.

3. In bowl of standing mixer fitted with whisk attachment, beat yolks at medium-high speed until just combined, about 15 seconds. With mixer running, add half the sugar. Continue to beat, scraping down sides of bowl as necessary until yolks are pale yellow and mixture falls in thick ribbon when whisk is lifted, about 8 - minutes. Add vanilla and beat to combine, - scraping down bowl once, about 30 seconds. Turn mixture into medium bowl; wash mixer bowl and whisk attachment and dry with paper towels. (If you have 2 mixer bowls, leave yolk - mixture in mixer bowl; wash and dry whisk attachment, and use second bowl in step 4.)

4. In clean bowl with clean whisk attachment, beat whites and cream of tartar at medium speed until foamy, about 30 seconds. With mixer running, add about 1 teaspoon sugar; continue beating until soft peaks form, about 40 seconds. Gradually add remaining sugar and beat until whites are glossy and - supple and hold stiff peaks when whisk is lifted, about 1 minute longer. Do not overbeat (if whites look dry and - granular, they are overbeaten). While whites are beating, stir chocolate into yolks. With rubber spatula, stir one quarter of whites into chocolate - mixture to lighten it. With a balloon whisk, fold in remaining whites until almost no streaks remain. Sprinkle dry ingredients over top and fold in quickly but gently with balloon whisk.

5. Pour batter into prepared pan; using an offset icing spatula and - working quickly, even surface and smooth batter into pan corners. Bake until center of cake springs back when touched with finger, 8 to 10 minutes, rotating pan halfway through baking. Cool in pan on wire rack for 5 minutes.

6. While cake is cooling, lay clean kitchen towel over work surface and sift remaining tablespoon cocoa over towel; with hands, rub cocoa into towel. Run paring knife around perimeter of baking sheet to loosen cake. Invert cake onto towel and peel off parchment.

7. Roll and fill cake. Set a large sheet of parchment paper on overturned rimmed baking sheet and set cake seam-side down on top. Trim and ice cake. Refrigerate baking sheet with cake, uncovered, to slightly set icing, about 20 minutes.

Using a knife, chop the chocolate into 1/4-inch pieces. Place the chocolate in a medium heat proof bowl. Bring the cream to a boil in a small saucepan over medium heat. The cream will actually rise up in the pan and look like it is beginning to boil over.

Immediately pour the boiling cream over the chopped chocolate. Tap the bowl on the counter to settle the chocolate into the cream, then let it sit for 1 minute. Using a rubber spatula, slowly stir in a circular motion, starting from the center of the bowl, and working out to the sides. Be careful not to add too much air to the ganache. Stir until all the chocolate is melted, about 2 minutes. It may look done after 1 minute of stirring, but keep going to be sure it’s emulsified.

Let the ganache sit at room temperature until it cools to 70 degrees F. In a 65 degree F room, this will take approximately 4 hours or 2 hours in the refrigerator. You can speed up the process by pouring the ganache out onto a clean baking sheet (thinner layers cool faster.) Once the ganache reaches 70 degrees F, it is ready to be used. At this point it can be covered and stored in the refrigerator for up to 2 weeks.

Stir the water and espresso powder in a large bowl to blend. Stir in the mascarpone. Using an electric mixer, beat the cream in another large bowl, while slowly adding powdered sugar, until soft peaks form. Using a large rubber spatula, fold 1/4 of the whipped cream into the mascarpone mixture to lighten. Then fold the remaining whipped cream into the mascarpone mixture.